1. Field
Embodiments of the present disclosure relate to a power supply circuit to protect a power factor compensation circuit from abnormal current.
2. Description of the Related Art
In general, an inverter is a voltage conversion device to convert a DC voltage into a 3-phase AC voltage (U, V and W) having a certain variable frequency and has been widely used in control of motors employed in electrical products such as washing machines, refrigerators, air conditioners or elevators due to energy efficiency and output control easiness.
A circuit to rectify a normal AC voltage into a DC voltage and to smooth the DC voltage is connected to an inverter. The voltage rectified and smoothed by the circuit is supplied to the inverter. The power factor of the rectifying circuit is as low as about 0.5 to 0.6. In addition, the power factor is decreased due to a phase difference between an input voltage (the normal AC voltage) and input current (normal AC current) and thus power consumption loss occurs due to reactive power.
In order to prevent such loss, an active power factor compensation circuit to improve a power factor using one inductor having a relatively small size and a switching element using the principle of a boost DC-DC converter was used. However, the active power factor compensation circuit is advantageous in that the inductor having a relatively small size is used and a DC voltage is greater than a peak voltage of an input voltage, but is disadvantageous in that efficiency is poor and switching frequency is increased in order to reduce ripple current generated due to switching of the inductor and thus switching loss is increased. In order to solve such disadvantages, an interleaved power factor compensation circuit to perform a power factor compensation operation by connecting two active power factor compensation circuits together in parallel has been developed.